Improvement in burglar-alarms



UN TED STATES PATENT OFFICE.

JAMES H. THORP, OF NEW YORK, N. Y., ASSIGNOR TO GEORGE B. FRY, OF

FRANKLIN, PENNSYLVANIA.

IMPROVEMENT IN BURGLAR-ALARMS.

Specification forming part of Letters Patent No. [74,594, dated March 7, 1876 application filed January 21, 1876.

' Alarms; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawing, and to the letters of reference marked thereon.

The nature of my invention consists in combining, with the detent of a stationary burglar-alarn1,a cord, a spiral spring, and a hinged lever, all as hereinafter more fully set forth. In order to enable others skilled in the art to which my invention appertains to make and use the same, I will now proceed to describe its construction and operation, referring to the annexed drawing, in which Figure 1 is a perspective view, showing in invention applied to a door. Fig. 2 1s an enlarged front view of the same. Fig. 3 is a perspective view of the hinged lever which is connected to the door. A.

A represents an ordinary door-casing, with door B hinged thereto, in the usual manner. 0 represents a burglar-alarm, of which D is the detent. From. the shaft of the detent D extends acord, or, which connects with one end ofa'coiled spring, E, the other end of said spring being, by a cord, b, connected with the outer end of a hinged lever, G.

The alarm is to be attached to the casing A, while the lever G is hinged to a'plate, d, which is fastened to the door B in any suitablemanner.

.the cord when the door is closed.

The alarm being wound up and the door closed, the hinged lever is'turned, as shown, away from the alarm, when the tension of the spring E tightens the cord a I), and holds the detent so that the alarm cannot operate. When the door is opened the cord slacks and the alarm sounds.

During the daytime, or when it is not desired to have the alarm in operation, a stoplever, H, pivoted to the alarm, is turned so as to hold the detent, and the hingedlever G is thrown open, so as to have no tension on At night, and other times when itis desired to have the alarm sounded, the hinged lever G is closed toward the door, so as to distend the spring and cause the alarm to be sounded whenever the door should be opened.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is v In combination with a burglar-alarm bell,-

O, the hinged lever G, attached to a door, and connected, by means of therod or cord 1), to a coil-sprin g, E, said-sprin g being connected, by a cord or wire, a, to a device or detent, whichoperates the burglar-alarm, all constructed and used substantially as set forth.

In testimony that I claim the foregoing I have hereunto set my hand this 3dday of December, 1875.

JAMES H. THORP.

Witnesses: I

RICHARD VAN DUSEN, J. O. ARMITAGEL 

